1. Execution Environment: AWS Lambda is a serverless computing service, where the code is executed on demand in response to events without the need to provision or manage servers. On the other hand, Docker requires the creation of a container that encapsulates the application along with its dependencies, allowing it to be run consistently across different environments.
2. Scalability: AWS Lambda automatically scales based on the incoming traffic and events, allowing for high availability and efficient resource utilization. In contrast, Docker containers need to be managed and scaled manually, requiring more hands-on configuration and monitoring for achieving scalability.
3. Billing Model: AWS Lambda follows a pay-per-use pricing model, where users are charged based on the number of invocations and the resources consumed during the execution of functions. Docker, being a containerization platform, does not have a distinct billing model as it can be used on various hosting services with different pricing structures.
4. Isolation: AWS Lambda provides a high level of isolation between function executions by spinning up a new container for each function, ensuring security and preventing interference between different invocations. Docker also offers isolation through containers, but the level of isolation can vary depending on the configuration and setup of the containers.
5. Deployment Flexibility: AWS Lambda functions can be easily deployed and managed through the AWS Management Console or command-line tools, allowing for quick updates and version control. On the other hand, Docker containers provide more flexibility in deployment options, as they can be deployed on different hosting platforms and managed using container orchestration tools like Kubernetes or Docker Swarm.
6. Startup Time: AWS Lambda functions have a cold start problem where the first execution of a function may experience a delay due to the initialization of resources. Docker containers, once created, have faster startup times as they do not incur the overhead of spinning up a new environment for each execution.

In Summary, the key differences between AWS Lambda and Docker lie in their execution environment, scalability, billing model, isolation, deployment flexibility, and startup time.